Apparatus for monitoring the condition of a machine

Abstract

A method for analyzing the condition of a machine, and an apparatus for analyzing the condition of a machine are described.

The invention claimed is: 
     
       1. A system for detecting an operating condition of a machine including a bearing associated with a shaft that rotates at a speed of rotation, the system comprising:
 a vibration sensor configured to detect mechanical vibrations responsive to the rotation of the shaft with respect to the bearing; 
 an analog to digital converter configured to generate a digital measurement signal having sample values responsive to the detected mechanical vibrations so that said digital measurement signal includes a vibration signal signature; and 
 one or more hardware processors configured to:
 generate an output value based on at least one of said sample values selected from a first temporal portion of the digital measurement signal; 
 generate a transformed signal based on a second temporal portion of said digital measurement signal; and 
 coordinate the generation of said transformed signal with the generation of the output value so that the second temporal portion is based on said first temporal portion of the digital measurement signal. 
 
 
     
     
       2. The system according to  claim 1 , including
 a first hardware processor location, 
 a second hardware processor location, said second hardware processor location being separated from said first hardware processor location by a geographic distance, and 
 a communications network, wherein 
 said one or more hardware processors include
 a first hardware processor at said first hardware processor location, and 
 a second hardware processor at said second hardware processor location, and wherein 
 
 said vibration sensor and said analog to digital converter are located at said first hardware processor location; and 
 wherein said first hardware processor has a first communications port for data exchange via said communications network, and 
 wherein said second hardware processor is located at said second hardware processor location, said second hardware processor having a second communications port for data exchange via said communications network. 
 
     
     
       3. The system according to  claim 2 , wherein said first hardware processor is configured to communicate with said second hardware processor via said communications network, said first hardware processor being configured to deliver measurement data being partly processed so as to allow further signal processing and/or analysis to be performed at the second location by said second hardware processor. 
     
     
       4. The system according to  claim 1 , wherein said one or more hardware processors being further configured to:
 generate an enveloped digital measurement signal based on said second temporal portion of said digital measurement signal; and 
 generate said transformed signal based on said enveloped digital measurement signal. 
 
     
     
       5. The system according to  claim 1 , wherein said one or more hardware processors being further configured to:
 generate an enveloped digital measurement signal based on said second temporal portion of said digital measurement signal; and to 
 generate a decimated enveloped digital measurement signal based on said enveloped digital measurement signal; and 
 generate said transformed signal based on said decimated enveloped digital measurement signal. 
 
     
     
       6. The system according to  claim 1 , wherein said one or more hardware processors are configured to output an indication of said operating condition based on said output value and said transformed signal. 
     
     
       7. The system according to  claim 1 , further comprising
 a user output interface configured to display an indication of said operating condition based on said output value and said transformed signal. 
 
     
     
       8. The system according to  claim 1 , wherein said output value and said transformed signal provide mutually different perspectives on the same event. 
     
     
       9. The system according to  claim 1 , wherein said vibration signal signature has at least one vibration signal repetition frequency and at least one vibration signal amplitude, and wherein
 said transformed signal is indicative of said at least one vibration signal repetition frequency. 
 
     
     
       10. The system according to  claim 1 , wherein said one or more hardware processors are configured to extract a value from said transformed signal. 
     
     
       11. The system according to  claim 1 , wherein said one or more hardware processors being configured to extract at least one vibration signal repetition frequency value from said transformed signal. 
     
     
       12. The system according to  claim 1 , wherein at least one of said one of said one or more hardware processors is embodied by a Digital Signal Processor. 
     
     
       13. The system according to  claim 1 , wherein said output value is an amplitude value. 
     
     
       14. The system according to  claim 1 , wherein said output value is a peak amplitude value. 
     
     
       15. The system according to  claim 1 , wherein said one or more hardware processors being configured to perform trending based on a current peak amplitude value and historical peak amplitude values retrieved from a memory. 
     
     
       16. The system according to  claim 1 , wherein said transformed signal is a Fourier transform. 
     
     
       17. The system according to  claim 1 , wherein said transformed signal is a fast Fourier transform. 
     
     
       18. The system according to  claim 1 , wherein said vibration signal signature has
 at least one vibration signal repetition frequency and at least one vibration signal amplitude; and wherein 
 said one or more hardware processors being further configured to: 
 generate an enveloped digital measurement signal based on said second temporal portion of said digital measurement signal; and 
 generate said transformed signal based on said enveloped digital measurement signal, said transformed signal being a fast Fourier transform, and wherein 
 said one or more hardware processors are configured to extract at least one vibration signal repetition frequency value from said transformed signal, and wherein 
 said output value is a peak amplitude value, said peak amplitude value being based on said at least one vibration signal amplitude. 
 
     
     
       19. The system according to  claim 18 , including
 a first hardware processor location, 
 a second hardware processor location, and 
 a communications network, wherein 
 said one or more hardware processors include
 a first hardware processor at said first hardware processor location, and 
 a second hardware processor at said second hardware processor location, and wherein 
 
 said vibration sensor and said analog to digital converter are located at said first hardware processor location; and 
 wherein said first hardware processor has a first communications port for data exchange via said communications network, and 
 wherein said second hardware processor is located at said second hardware processor location, said second hardware processor having a second communications port for data exchange via said communications network, wherein 
 said first hardware processor is configured to communicate with said second hardware processor via said communications network, said first hardware processor being configured to deliver measurement data being partly processed so as to allow further signal processing and/or analysis to be performed at the second location by said second hardware processor. 
 
     
     
       20. The system according to  claim 19 , further comprising a user output interface configured to display an indication of said operating condition based on said peak amplitude value and said vibration signal repetition frequency value. 
     
     
       21. A method for detecting an operating condition of a machine including a bearing associated with a shaft that rotates at a speed of rotation, the method comprising:
 generating, by way of a vibration sensor applied to a measuring point on the machine, an analogue measurement signal responsive to mechanical vibrations emanating from the bearing during rotation of the shaft so that said analogue measurement signal includes a vibration signal signature having a vibration signal repetition frequency and a vibration signal amplitude; 
 sampling, by way of an analog to digital converter, said analogue measurement signal; 
 generating, from said sampling, a digital measurement signal having sample values responsive to the detected mechanical vibrations so that said digital measurement signal includes said vibration signal signature; 
 generating, by way of one or more hardware processors, a peak amplitude value based on a first temporal portion of the digital measurement signal; 
 generating, by way of said one or more hardware processors, a Fourier transformed signal based on a selected second temporal portion of said digital measurement signal; and 
 coordinating, by way of said one or more hardware processors, the generation of said Fourier transformed signal with the generation of said peak amplitude value so that said transformed signal and said peak amplitude value are based on the same or substantially the same temporal portion of the digital measurement signal. 
 
     
     
       22. The method according to  claim 21 , further comprising generating, by way of said one or more hardware processors, a first condition value which is indicative of said peak amplitude value, and
 generating, by way of said one or more hardware processors, an output which is indicative of said vibration signal repetition frequency. 
 
     
     
       23. The method according to  claim 22 , further comprising delivering, by way of said one or more hardware processors, said peak amplitude value and said output indicative of said vibration signal repetition frequency to a display, and
 presenting, by way of said display, said peak amplitude value and said output indicative of said vibration signal repetition frequency on said display. 
 
     
     
       24. The method according to  claim 21 , wherein said Fourier transformed signal is a fast Fourier transform, said method further comprising
 extracting, by way of said one or more hardware processors, at least one vibration signal repetition frequency value from said fast Fourier transformed signal, said at least one vibration signal repetition frequency value being indicative of said at least one vibration signal repetition frequency. 
 
     
     
       25. The method according to  claim 22 , wherein transmitting, via a communications port and a communications network, said first condition value and said output indicative of said vibration signal repetition frequency from a first location to a second location. 
     
     
       26. A system for detecting an operating condition of a machine including a bearing associated with a shaft that rotates at a speed of rotation, the system comprising:
 a vibration sensor configured to detect mechanical vibrations responsive to the rotation of the shaft with respect to the bearing; 
 an analog to digital converter configured to generate a digital measurement signal having amplitude sample values responsive to the detected mechanical vibrations so that said digital measurement signal includes a vibration signal signature; and 
 one or more hardware processors configured to:
 generate a smoothened digital signal based on said digital measurement signal so that an output sample amplitude value is adjusted upwards in dependence on
 the amplitude of the corresponding input sample amplitude value and in dependence on 
 the amplitudes of temporally adjacent input sample amplitude values; 
 
 generate an asymmetrically filtered signal based on the smoothed digital signal so that
 a first settable filter value is set to a first value in response to a detected positive time derivative of the smoothened digital signal; and 
 said first settable filter value is set to a second value in response to a detected negative time derivative of the smoothened digital signal; 
 
 detect peak values in said asymmetrically filtered signal, and 
 deliver output peak values based on said detected peak values.